In the last years, a lot of effort has been put in the synthesis of one-dimensional nanostructures such as nanowires. Due to their restricted size, these structures exhibit novel physical and chemical properties, and have opened up a large new field of basic research as well as possible applications. Electro-chemical deposition (ECD) is becoming an increasingly attractive method for the synthesis of new materials and nanostructures. ECD has been shown very suitable for the fabrication of metal, alloy and compound nanowires in high-aspect ratio nano-structured porous templates (for instance anodized alumina). Single crystals were grown in template pores of micrometer length at room temperature by using commercial baths and reverse pulse plating in ultrasonic fields.
In Adv. Mater. 2001, 13(1), 62-65 Molares et al. report the fabrication of cylindrical poly- and single-crystalline copper wires, by means of the template method, with diameters between 60 and 500 nm and aspect ratios (length to diameter) up to 500 nm.
However, all the template-assisted or through-hole electro-depositions methods mentioned in the prior art still suffer from the fact that a “cap” is typically formed on top of the template or mask as soon as the nanowires or studs grow out of the pores or holes.